To make fans work quietly, manufacturers use slow-running motors to spin the blades. This reduces noise but also reduces power, producing weak airflow. To make powerful fans, they use fast motors to spin the blades.
But fast motors create more noise. Powerful and quiet is very difficult to achieve in a conventional fan. The new Dyson Cool fans have been engineered to be quieter, and use a brushless DC motor that consumes 30% less energy than AM01 – yet generate powerful airflow.